Missing support for trim method.

[rayniel95]

I do not sure if this is a bug or a feature (according to #47 (comment)). But if I execute:

import airspeed

t = airspeed.Template("""
#set($some="      some  ")
$some.trim()
$some.strip()
""")
people = [{'name': 'Bill', 'age': 100}, {'name': 'Bob', 'age': 90}, {'name': 'Mark', 'age': 25}]
print(t.merge(locals()))

the output is:

$some.trim()
some

so, for some reason the trim method used to remove white spaces in Java need to be changed to its Python equivalent.

[purcell]

There are some extra string methods already, see here — if you'd like to submit a PR with a couple of little tests, I'd be happy to incorporate it.