fastfloat: parse "infinity" in fastfloat.Parse() function

fastfloat: support parsing "infinity" strings

This is needed for OpenMetrics - see https://github.com/OpenObservability/OpenMetrics/blob/master/OpenMetrics.md#abnf

report more errors when parsing numbers

Previously numbers' parsing could miss parse errors. Properly handle such cases now.

Updates VictoriaMetrics/vmctl#25

fastfloat: add Parse(), ParseUint64() and ParseInt64() functions, whi…

…ch return parse errors

fastfloat: properly parse `+Inf` values by ParseBestEffort()

Updates VictoriaMetrics/vmctl#25

Perform conversion from string to []byte according to rule #6 at http…

…s://golang.org/pkg/unsafe/#Pointer

Remove accidentally added TestParseFuzz

Remove accidentally added code at parser_timeing_test.go

fastfloat: properly parse floating-point number with '.e' inside like…

… '1.e4'

Updates #55