Fix REST API for WSGI Add dictionary-like headers attribute. Similar to the apache implementation in same directory but we look up the given header in the wsgi environment. Environment entries are mangled (all uppercase, '-' replaced with '_', prefix HTTP_). So on lookup we mangle the given name first. This allows the rest implementation (and others) to look up headers.

{
    "validthis": true,
    "laxcomma" : true,
    "laxbreak" : true,
    "browser"  : true,
    "eqnull"   : true,
    "debug"    : true,
    "devel"    : true,
    "boss"     : true,
    "expr"     : true,
    "asi"      : true
}