- made chdir use FS.chdir
 - changed direct references to FS.currentPath to use FS.cwd()
 - fixed mountpoint resolving in mount
 - added async FS.syncfs
 - added idbfs and nodefs
 - minor coding convention fixes
- updated several unistd tests to test against NODEFS
 - added test for FS.syncfs functionality
 - added basic nodefs r/w test
Merge pull request #1601 from inolen/idbfs

NODEFS and IDBFS support
 - append to Building.COMPILER_TEST_OPTS for unistd tests