add sanity check for left extrapolation
allow for construction by expiry date and for receiver and payer swaptions
add missing return statement
Merge pull request #51.
add -fPIC to java compile
Merge pull request #52.
Upgrade QuantLibXL and its dependencies to Visual Studio 2012
Added the flag to the command line.

The command is already hard-coded anyway.
Merge pull request #53.
Removed user-preference files from version control
Merge pull request #54.
add diamond jubilee bank holiday to London calendar
Merge pull request #55.
Merge branch 'master' of https://github.com/lballabio/quantlib
fixed HKD conventions, added fixings, smoothed out few issues