[#120] Allow donations to fully fund projects

Add Project.amount_needed_to_fully_fund_via_paypal() and
Project.amount_needed_to_fully_fund_via_ideal() that calculate how
large a donation is needed to fully fund the project when transaction
fees are included

Add settings for the transaction fee calculations

Add text to donation form page that tells the user how much is needed
to fully fund the project including projected transaction fees using
the methods above

Change the validation to allow for the "overfunding" above

Fixes related to the switch of memcached library
[#120] Bugfix to MOLLIE_FEE_BASE setting

Re-naming of setting wasn't done everywhere
Add lxml to pip requirements

lxml was mistakenly removed some time ago, putting it back
Change lxml version

Change back to lxml version 2.3.6 for compatibility with Splinter
Hotfix 2.1.2.1 - Donating to 100%

Adding Release notes for the Donations to 100% hotfix applied on 4th February 2013.
adding name
Merge branch 'hotfix/2.1.2.1'
Put back limit=100 for global maps

Set limit = 100 for number of records to fetch to global maps in one
API call.