Issue100 patch

[yeoupooh]

Possible fix for #100.

[magnuspalmer]

I ran into this as well but this is almost already built in, only changed needed(?) would be to make it settable in the HTTP class.

package wslite.http
class HTTP {
    static final String DEFAULT_CHARSET = 'ISO-8859-1' // http://tools.ietf.org/html/rfc2616#section-3.7.1

Anyway, a workround is to do something like: HTTP.metaClass.'static'.getDEFAULT_CHARSET = { -> 'UTF-8' }

A more complete workaround example would be:
Gist