Add missing BITFeedbackManagerDelegate.h import in HockeySDK.h and fix @protocol statement that was added as @class

Fixes https://github.com/bitstadium/HockeySDK-iOS/issues/63
Consider Feature defines in BITHockeyManagerDelegate.h
Add missing Security framework to podfile
Fix removing observers correctly

Thanks to @idpaterson for reporting this in https://github.com/bitstadium/HockeySDK-iOS/pull/64
FIx usage value being reset on every app cold start
Add namespace to local methods and make the C function static to avoid linker problems when adding similar libraries using PLCR
Switched back to s.resource_bundle in podspec to remove deprecation warning on installation via cocoapods.
Merge pull request #66 from elektrojunge/develop

Switched back to s.resource_bundle in podspec to remove deprecation warning on installation via cocoapods
Removed no longer necessary prepare_command from podspec
Merge pull request #67 from elektrojunge/develop

Removed no longer necessary prepare_command from podspec
If the parentViewController onto which a modal view will be presented is still being presented, try again a little later

This fixes crashes when automatically presenting our view controllers on top of the current parentViewController while that is still in the process of being presented (animated).
Add some documentation to the last commit and note it doesn't work on iOS 5
Fix memory leak in BITKeyChainUtils

Fixes https://github.com/bitstadium/HockeySDK-iOS/issues/68
Added more documentation to BITCrashManager

- added information about which protocol allows it to add custom username/email/userid to crash reports
- added information on how to handle crashes that happen during startup
[Authenticator] also check the host part of a given URL

This helps especially in case of a custom URL scheme, so that
BITAuthenticator doesn't reset the identification token if a URL
is passed in that wasn't meant to parsed by BITAuthenticator.

fixes #70
More documentation updates
Localization string updates, translations pending
Fix update view controller not showing updated content after using the check button and actually receiving new content
Provide public access to the anonymous UUID being used

This UUID is app installation specific and being used for crash reports and when sending feedback.
Fix crash if minOSVersion is not provided