Update indexes at query time

Update documentation to explain when indexing is done
Merge pull request #76 from cloudant/30106-update-indexes-at-query-time

Update indexes at query time
Fix typo in ChangeLogLevel Macro
Prepare for 0.10.0
Add source line to prevent CocoaPods warning
Declare version number in one place: version.h

Also return platform and version number in user agent header