Script improvement

[jifang]

1. Update the python script for generating the string file from swift source. Now, it supports generating string from multiple inputs. The usage is similar to the Apple's genstrings tool. Usage: find /path/to/source -iname "*.swift" | xargs python ./genstrings_swift.py -o ./App/en.lproj/ ./App/Source/LocalizationConstants.swift
2. Fix the bug in python script for merging the string file. When the string value contains escaped double quotes, it will be excluded from the string file. For example, following lines will be striped from the final output /* String with quotes */ "EscapedQuotes" = ""String with quotes"";

[philippb]

Thank you. We try to look into it this week.