Since the directory monitoring is now basically working we remove the
project scan thread periodically scanning the project directory.
Each project's directory is scanned only once at the beginning when
calling the function `core.add_project_directory` and is updated
incrementally when directory change events are treated.
The config variable `project_scan_rate` is removed as well as the
function `core.reschedule_project_scan`.
Useful to draw whitespaces with alternate characters and colors
without slowing down the text rendering.
A new API is implemented. A renderer.replacements object can be created
to list the replacements.
In turns the function renderer.draw_text and draw_text_subpixel now accept
two optional arguments for replacements.
To avoid excessive memory usage when opening in a directory with too many files.
Introduce the config variable config.max_project_files to choose the limit.
The mechanism introduced avoid using excessive memory but it fails to
let user access all the files in the directory. A better implementation
should not impose any limits but read each subdirectory on-demand, only
as they are expanded in the tree-view.
Filenames that match either the single pattern provided by
`config.ignore_files`, or any pattern in a table of patterns, will be ignored
when lite is filling the `core.project_files` table
Resolves#77Resolves#102