Update send_mail_template to pass optional email headers to the EmailMultiAlternatives constructor.  Rather than having the form page_processor send mail from user submitted email addresses (if present) have it specify the Reply-To header.

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branch : forms_reply_to
Fix UnicodeDecodeError for python3 setup.py bdist_rpm

`python3 setup.py bdist_rpm` gave the following error:

	Traceback (most recent call last):
	  File "setup.py", line 60, in <module>
	    long_description=open("README.rst").read(),
	  File "/usr/lib64/python3.3/encodings/ascii.py", line 26, in decode
	    return codecs.ascii_decode(input, self.errors)[0]
	UnicodeDecodeError: 'ascii' codec can't decode byte 0xc3 in position 11646: ordinal not in range(128)

While Python3 is unsupported yet, why not make it easier in the future?
Get rid of FORMS_DISABLE_SEND_FROM_EMAIL_FIELD, always add the Reply-To header if there is an email_to.

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branch : forms_reply_to
Adding template accessible settings into context for rendering templates for emails.
Adding .control-label to form_fields.html
Indent .control-label
Added Cristian Ciupitu to AUTHORS
Merge.
Merged in joshcartme/mezzanine/forms_reply_to (pull request #49)

Forms Reply-To rather than replying as
Merge.
Merge.
Added Danny Sag to AUTHORS
Be a bit more explicit with request arg in settings context processor.
Merge.
Added Troy Harvey to AUTHORS.