Use boost::filesystem::path for all paths, and std::string for all other
strings, converting to/from wxString as close to the actual uses of wx
as possible.
Where possible, replace the uses of non-UI wxWidgets functionality with
the additions to the standard library in C++11, or the equivalents in
boost.
Move the path token management logic to libaegisub (and rewrite it in
the process).
Add a basic thread pool based on asio and std::thread to libaegisub.
This touches nearly every file in the project and a nontrivial amount of
code had to be rewritten entirely, so there's probably a lot of broken
stuff.
Add agi::ProgressSink and agi::BackgroundRunner interfaces to libaegisub
which represent a generic progress sink and a thing which calls funtions
that need progress sinks. Make DialogProgress implement
agi::BackgroundRunner, invoking the passed function on a worker thread
and giving it a progress sink to update the dialog with.
Rewrite Automation4::ProgressSink, LuaThreadedCall and all related
classes to be based on agi::ProgressSink. Automation now simply uses
DialogProgress (although that's merely an implementation detail) and
adds a single method to route dialog opening from the worker thread to
the GUI thread.
Originally committed to SVN as r5634.