Numbers with leading zero

[dariodsa]

Currently tomland interprets decimal numbers with leading zeros into zero. That is not really in the spirit of a TOML-0.5.0. According to the documentation:

Leading zeros are not allowed. Integer values -0 and +0 are valid and identical to an unprefixed zero.

For this behaviour is responsible zero parser in function decimalP.

tomland/src/Toml/Parser/Value.hs

Lines 37 to 38 in 316c893

	zero, more :: Parser Integer
	zero = 0 <$ char '0'

So the type of parser should allow leading zero only if it is the only digit in the number, otherwise it shouldn't be allowed to come first.

[chshersh]

Resolved by #344