Squashed commit of the following:

commit 9cd79c848d2583d9d0b6590fb81d9771512c3125
Author: suhorng <suhorng@gmail.com>
Date:   Sat Jan 4 11:40:41 2014 +0800

    add initialization tests

commit 72bcb77befd9a7ebfad394341bb0fc0f6f11d578
Author: suhorng <suhorng@gmail.com>
Date:   Sat Jan 4 11:32:13 2014 +0800

    fix global variable initialization

commit 240c6bbf9b97588148e66d2a8535cc3eaf760bce
Author: suhorng <suhorng@gmail.com>
Date:   Sat Jan 4 10:41:29 2014 +0800

    fix variable initialization type conversion bug

commit 74e5babd74a471d8912cb67116574b5a1df3d751
Author: suhorng <suhorng@gmail.com>
Date:   Sat Jan 4 02:23:03 2014 +0800

    move Test.hs to Language.BLang.Debug