Issue #168 : math.random(upper) now works fine when upper=1

[gudvinr]

Fixes #168.

Changes proposed in this pull request:

• a math.random now confoorms lua docs

[coveralls]

Coverage remained the same at 90.284% when pulling d985e1d on gudvinr:feature/168_random into 84ea3a3 on yuin:master.

[coveralls]

Coverage remained the same at 90.284% when pulling d985e1d on gudvinr:feature/168_random into 84ea3a3 on yuin:master.

[coveralls]

Coverage remained the same at 90.284% when pulling 921e332 on gudvinr:feature/168_random into 84ea3a3 on yuin:master.

[yuin]

Sorry for late reply. Could you add tests to _glua-tests/issues.lua ?

[gudvinr]

@yuin done