readme: reference windows build instructions

also change ~/ -> %APPDATA% for pidgin on windows
added note that keysync does not address OTR issues with multi-party (closes #20)

Added some language to further clarify what syncing OTR identity and trust
relationships means, and added language to clarify what KeySync is *not*
meant to do.

thanks to the.solipsist for contributing to this.
adium: fix error in Accounts.plist test data that was manually edited
add curated files to set up 'sameness' test
alphasort the whole keydict before outputing files

This makes it easier to compare previous versions of the files since the
order should stay the same.  This also makes writing tests easier.
write test of 'sameness', keysync should gen same file that it reads

for example, `keysync -i pidgin -o pidgin` should generate the exact same
files, given that the input file is alphasorted.  This test currently fails
for a number of reasons, so it does not report as broken yet (|| true).
pidgin: update logic for including XMPP Resource to get correct output

Pidgin sometimes requires that the XMPP Resource is included in the
account name in OTR files.  This updates the code to do this correctly in
the cases that I am aware of.
use keydict key as canonical account name, key['name'] stores the app's name

For example, Adium uses account numbers, so given a keydict key of
gptest@jabber.org, a key read from Adium will have something like
key['name'] == 1
add tests for sameness between adium and pidgin, refs #1888

This shows that we have work to do:

* a lookup table for app-specific protocol names, refs #1964
* support multiple keys per id/name, refs #1871, #1868
* figure out zero padding problems, refs #1867