More robust handling of asymptote code
Revised dependency checking.

- Now works recursively.

- Checks import statements directly, instead of using a comment tag.

- Decides which modules are "local" based on which files exist.
Fixed the asy dependency code
Set ASYMPTOTE_DIR when necessary.
Removed some debugging outputs.
Updated change log.
Merge branch 'Nick' of upland.cse.sc.edu:texmake into Nick

Conflicts:
	texmake
Completed partial merge.