Fixed error when project does not build.
Fixed some warnings.
Fixed issue # 4.
Fixed issue # 6.
Removed redundant parameter.
Fixed issue # 8.
Fix of previous commit.
Refactoring of ThrowIfNumberIsNegative method.
Refactoring: removed duplicated methods with the same functionality but different signature.
1. Fixed bug # 7.
2. Parse poll attachments from wall post.
Merge branch 'master'