Added support for reading and writing _CoqProject files

Kopitiam needs somewhere to put its project-specific configuration, and
the _CoqProject file seems to be a good place
Use a 64-character buffer when reading responses from coqtop

Until now, Kopitiam had been reading responses character-by-character, so
this commit should somewhat improve the I/O performance
Don't erroneously preserve backslashes when parsing CoqProject files
Added _CoqProject support to the CoqProjectImpl class

CoqProjectImpl can now -- optionally -- read its load path configuration
from the _CoqProject file. Editing this file doesn't yet cause CoqBuilder
to be triggered, however
Increased the coqtop buffer size "slightly"

The coqtop buffer size is now 32K (five hundred and twelve times larger).
This change has two practical upshots: shorter goals can now be read
instantaneously, and longer goals don't freeze Kopitiam
Convert coqtop end-of-stream errors into normal CoqTypes.Fail results

This stops the code from failing with a mysterious NullPointerException if
the underlying coqtop instance goes away
Replaced the Coq restarting action with a Coq stopping action

The Coq editor starts Coq on demand, so an explicit restart action is
unnecessary. (This is a more useful action anyway, as it gives Windows
users a way of stopping an out-of-control coqtop process!)
Don't create error markers if the underlying coqtop process was stopped
Don't mark generated Coq project Makefiles as derived resources

Derived resources are normally automatically excluded from version control,
and we really don't want that to happen for Makefiles
Fixed a bug in the Makefile load path generation code

Logical directories are now included in the COQFLAGS options
Added a keyboard shortcut for the "Set Printing All" command
Removed some leftover debugging code

This commit also fixes a minor problem in the manifest introduced by the
last commit
Added some more utility methods to the CoqTopIdeSlave_v20120710 trait

The trait now has some convenience methods for retrieving option states and
values
Removed the extra option cache from ToggleCoqFlagHandler

OptionalCoqTopIdeSlave_v20120710 already implements an option cache:
there's no good reason to have another one in the handler
Added a keyboard shortcut for the "Set Printing Implicit" command
Added a refreshElements method to the UIUtils class

The second argument of ICommandService.refreshElements isn't exposed by
this method, because Kopitiam doesn't need it (yet)
Added a hook to EditorHandler for detecting when the active editor changes

Some handlers need to update their state -- or the state of their
associated UI elements -- when the editor changes. This hook makes that
easy
Update ToggleCoqFlagHandler's UI elements when the active editor changes
Bumped the version number to 0.3.6 and added a changelog entry