Add UnnecessaryMantissa linter

Checks for the unnecessary use of a zero-value fractional component
(a.k.a mantissa) in a number. Thus it will prefer "4" over "4.0".

Change-Id: Ic174a6ef17533bfc9f8072198d7f8b3a5697328a
Reviewed-on: http://gerrit.causes.com/37221
Tested-by: jenkins <jenkins@causes.com>
Reviewed-by: Shane da Silva <shane@causes.com>