Add support for explicit 'write flush' used to flush HTTP headers...

... without a subsequent write.

Ensure MessageDecoders are being called for all read HTTP header values (not just regular expression decoders).
Move leading and trailing forward slashes for regular expression literals from Regex grammar to Robot grammar and enhance pattern characters.
Align NamedGroupPattern.compile(input) with Pattern.compile(input) syntax - no leading and trailing forward slashes on input for either.
Relax requirement to close each stream explicitly in script, tidy up automatically at end of test instead.
Support custom EL functions in the same project as scripts using them.
Rename goal mojos to remove robot from name.
Use maven.k3po.daemon and maven.k3po.verbose properties instead of maven.robot.daemon and maven.robot.verbose.
Add support for coercing byte arrays in EL to UTF-8 strings.