remove regexp for performance

[markrechler]

While the regex version reads easier, the performance difference is very noticeable even for these easy replacements.

master:
BenchmarkManyDifferentSensors          1    1928148881 ns/op
BenchmarkOneBigTimer           1    1845274355 ns/op
BenchmarkLotsOfTimers          1    1902944310 ns/op
BenchmarkParseLine    300000          5568 ns/op

non_regex:
BenchmarkManyDifferentSensors          1    1838807819 ns/op
BenchmarkOneBigTimer           1    1769153610 ns/op
BenchmarkLotsOfTimers          1    1853729588 ns/op
BenchmarkParseLine   1000000          1131 ns/op

[markrechler]

@jehiah this is ready for review. Thanks.

[davemarchevsky]

I think you might be able to do something like

c >= byte('a')

instead of

c >= 97

for dat readability

[mreiferson]

and out of the shadows stood @davemarchevsky

[markrechler]

Adjusted, thanks @davemarchevsky.

[jehiah]

🔨 ?

[markrechler]

Squashed.