Feature/progress management

[ThomasKroes]

Main subjects of this PR:

1. New API for creating, monitoring, and interacting with tasks
2. Revamped splash screens (application + project) which make use of the new tasks API
3. Various bug fixes

New API for creating, monitoring, and interacting with tasks

1. A task manager has been added to the core interface which keeps track of all the tasks in the system (see hdps::tasks())
2. A basic set of tasks has been added (but for very specific behavior a custom task can be implemented)
3. Each task has one of the following states:
   • Undefined tasks have not been initialized.
   • Idle tasks are operational and ready to be started.
   • Running tasks are tasks for which the amount of work is known a priori.
   • RunningIndeterminate tasks have no a priori known amount of work.
   • Finished tasks have completed all the work.
     Note: call setFinished(...) to flag a task as complete
   • Tasks are set to AboutToBeAborted just prior to them being aborted.
   • Aborting tasks are in the process of being aborted.
   • Aborted tasks have been forcefully and successfully killed.
4. Each task has a GUI scope in which it operates (see getGuiScope(...) and getGuiScope(...)):
   • None: these tasks are not associated with any GUI context.
   • Background: The aggregated progress and status of background tasks with statuses Running, RunningIntermediate, and Finished are displayed in the ManiVault status bar as a progress bar.
   • Foreground Tasks with statuses Running, RunningIntermediate, and Finished are displayed in the ManiVault status bar as a tool button with a popup widget that shows them.
   • Modal tasks with statuses Running, RunningIntermediate, and Finished are displayed in a modal ManiVault status bar as a tool button with a popup widget that shows them.
5. In total there are three modii with which the task progress can be computed:
   • Manual: the developer calls setProgress(...) to manually set the progress (this is the default modus).
   • Subtasks: a fixed number of tasks is assigned with setSubtasks(number_of_tasks) or setSubtasks(string_list) and subsequently flagged started with one of the setSubtaskStarted(...) overloads and flagged finished with one of the setSubtaskFinished(...) overloads. The progress percentage will be computed automatically.
     Note: the task progress mode is automatically set to Subtasks when either setSubtasks(number_of_tasks) or setSubtasks(string_list) is called.
   • Aggregate: the progress of a task is automatically computed on the basis of its child tasks (which are enabled).
     Note: the task progress mode is automatically set to Aggregate when a child task is added.
6. For more in-depth exploration and control over tasks, a tasks plugin has been added.

Revamped splash screen API (application + project) that makes use of the new tasks API

1. Fully customizable splash screen that can be used in various scenarios:
   • During the startup of ManiVault:
     • Shows application info (i.e., application name, version, loaded plugins, copyright notice) when loaded with project
     • Shows project information (i.e. title, description, logos) when a project is loaded during startup (with HDPS.exe -p <file_path> or HDPS.exe --project <file_path>)
   • From within the application itself (no progress bar is shown):
     • When a project is loaded: Help > About Project
     • Help > About ManiVault
2. The splash screen has an API to add alerts (styled according to their type i.e. Info, Debug, Warning). For instance, warnings will be added if one or more plugins cannot be loaded.
3. Restyling of background (in accordance with start page background) and some HTML text styling.

Various bug fixes

1. The problem with slow loading of the application has been solved
2. Other bugs here and there