change architecture to default

this enables ShareKit to build with armv7 and armv7s on current Xcode
remove armv6 for remaining targets

all targets are now armv7, armv7s
change deployment target to 4.3
Protect against nil being passed to [SHK error:]
Merge pull request #651 from rockabyte/projectsettings

change architecture to default for project and library target
Cleaned up example files - moved to right directory
Added documentation folder. Contents:

- new sharers templates, updated for SHK 2.0
- flowcharts, because download section on github is deprecated
Update README.md
Merge pull request #663 from scompt/nil_error

Protect against nil being passed to [SHK error:]