Add pre_package event to wp8 project

WP7 project was already done in commit: bd2c667e947b3fda05541e0d1a124d23df60a132
Wait for the pre_package event to finish, or the update_csproj function might give unexpected results.
Fixes both the wp7 and wp8 parser.
Code style (indentation)
CB-5183 WP7/8 custom_path is not correctly resolved by CLI
Merge branch 'CB-5183' of https://github.com/sgrebnov/cordova-cli
readability + code quality in wp7+8 parsers
merging