Merge pull request #18 from tomtung/master

Add unit testing support for C# (NUnit) and Java (JUnit)
[fix] method name of java unit test
[fix #17] regenerate code button behavior
[rewrite] code generation
[package structure] greed.code
[rewrite] use code transformer to perform all code transformation
[rename] unit test template
[new] .gitignore
[release] 1.3
[update] README for 1.3
[bug fix] BlockCleaner cleans the tags as well
[fix] library path
uniform version upgrading by a external file 'version'
fix run_arena script
[add] downloads page
[fix #20] template variable naming problem
[up] gradle 1.4
[fix] major bug
[up] Contest Arena version
[release] 1.3a