Bug 1022262 - Part 1: Rename in-tree Hunspell source files to match upstream. r=ehsan

--HG--
rename : extensions/spellcheck/hunspell/src/README.hunspell => extensions/spellcheck/hunspell/src/README.mozilla
rename : extensions/spellcheck/hunspell/src/affentry.cpp => extensions/spellcheck/hunspell/src/affentry.cxx
rename : extensions/spellcheck/hunspell/src/affixmgr.cpp => extensions/spellcheck/hunspell/src/affixmgr.cxx
rename : extensions/spellcheck/hunspell/src/csutil.cpp => extensions/spellcheck/hunspell/src/csutil.cxx
rename : extensions/spellcheck/hunspell/src/dictmgr.cpp => extensions/spellcheck/hunspell/src/dictmgr.cxx
rename : extensions/spellcheck/hunspell/src/filemgr.cpp => extensions/spellcheck/hunspell/src/filemgr.cxx
rename : extensions/spellcheck/hunspell/src/hashmgr.cpp => extensions/spellcheck/hunspell/src/hashmgr.cxx
rename : extensions/spellcheck/hunspell/src/hunspell.cpp => extensions/spellcheck/hunspell/src/hunspell.cxx
rename : extensions/spellcheck/hunspell/src/hunzip.cpp => extensions/spellcheck/hunspell/src/hunzip.cxx
rename : extensions/spellcheck/hunspell/src/phonet.cpp => extensions/spellcheck/hunspell/src/phonet.cxx
rename : extensions/spellcheck/hunspell/src/replist.cpp => extensions/spellcheck/hunspell/src/replist.cxx
rename : extensions/spellcheck/hunspell/src/suggestmgr.cpp => extensions/spellcheck/hunspell/src/suggestmgr.cxx
Bug 1022262 - Part 2: Update Hunspell to version 1.3.3. r=ehsan
Bug 1019996 - Remove an unnecessary call to AlignFixedAndStickyLayers. r=Cwiiis
Bug 1019996 - Apply overscroll effect to fixed and sticky layers. r=kats, r=Cwiiis