Prevent NPE on processResiultFromGallery when intent comes null

close #22
ios: Delete postImage (dead code)
CB-6875 android: Handle exception when SDCard is not mounted

close #29
Tweak docs to not use []'s for optional arg since that's JS array notation

close #21
CB-7071 android: Fix callback firing before CROP intent is sent when allowEdit=true
Merge branch 'master' of https://git-wip-us.apache.org/repos/asf/cordova-plugin-camera