Minimize/fix function declarations
Remove unused mark_current_freelist function
Give SHARED_LIST_SIZE a CGC_ prefix
Stop using printf in signal handler

1) Too verbose for GC heavy tests
2) Occasional deadlock on OS X
Change metor benchmarks to silence warning

ruby 2.0 warns about using class variables from top level.  Change
them to be globals.
Track GC runs for GC.stat
Ignore more build products
Remove unused variables
Update final and free counters
Use heap.free_min instead of custom FREELIST_MIN_SIZE
Merge remote-tracking branch 'origin/master'

Conflicts:
	.gitignore
Re-add files to ignore
Merge pull request #5 from Benabik/master

Miscellaneous Improvements