RunContext#inTempDir() now accept a callback

fix #722
0.18.4
Document mem-fs-editor in API doc, also remove references to src/dest object

Fix #727
Fix conflicter to allow skipping

Fix #725
RunContext now take a tmpdir setting to skip auto run in tmpdir

Fix #718
Update helper.run to pass settings to RunContext
0.18.5
Better method names
Fixed callback and and package.json dependencies installation
Merge branch 'fix-install' of https://github.com/rafacesar/generator into fix-install