fix(TomlTable): fixes key serialization by adding better key name checks

[tcortega]

Uses a foreach to iterate through the key strings both in the table and during object serialization to identify which keys needs to be quoted in a performative way.

~Also made a small optimization in the methods inside TomlUtils.~

The tests might not look that good, feel free to change it if you want. Or give me a heads up on what you have in mind for the tests.

Closes #30 Closes #31

[SamboyCoding]

Can you rebase this onto latest?

[coveralls]

coverage: 92.423% (+0.3%) from 92.162% when pulling bbbd3e056621bb7d8397a5de2281a8752179ccc7 on tcortega:fix/key-escaping-check into 4729d95582581b26d50e8d82de5b3ae6cf28ddb5 on SamboyCoding:master.