Fix issue #46

[eclipxe13]

The issue #46 is reproducible for any rule that:

1. extends AbstractRule
2. set the options using cvs syntax with only one parameter that casting to boolean returns false, specifically '0'

A workaround could be just use another notation, like 'min=0' or '{"min":0}'

But well, this fix prevents options to be rejected if the option is '0' and the rule has $optionsIndexMap declared and with a count greater than zero. In this special case then change the value of the options to the array of the first index of $optionsIndexMap as key and '0' as value.

[eclipxe13]

It also includes code style changes made by running phpcbf --standard=PSR2 ./src to allow travis to pass.

[adrianmiu]

@eclipxe13 Thank you