Quoted double parsing

[mark-b2c2]

Hey @zapov,

I was profiling an app of ours using your fantastic serialization library and I saw that deserializing quoted doubles was causing excessive creation of strings due to the code falling back to Double.parseDouble in parseDoubleGeneric.

Please take a look at this PR and advise if this approach looks reasonable and what else you think needs completing in order to consider merging the change.

[zapov]

Thanks for the PR.
Before merging I would like to see more tests, to cover various formats of double + this special cases of Infinity and NaN.
Plus would want to see some error handling, eg what if one writes Infinity without quotes, has 3 quotes instead of 2 and other edge cases which were previously covered by quoting.

[mark-b2c2]

Thanks for the feedback. I wanted to see if you were agreeable to the change to begin with.

I will improve test coverage in the next couple of days and revert when complete.