Solitude facade for pay providers (bug 987903)

There was an old universal provider API but it was
half baked and assumed that we would hide the details
of Bango behind Solitude. This new approach allows
for Bango to be unique while making room for
"standard" providers if we get them.
remove theme
Merge pull request #410 from andymckay/fix-docs

remove theme
add in boku (bug 989993)
Merge pull request #411 from andymckay/989993

add in boku (bug 989993)
Merge pull request #408 from kumar303/unipay

Solitude facade for pay providers (bug 987903)
Force python 2.7 in CI
jenkins.sh is not in use, merged it to CI script
 Update CACHES default BACKEND to use pylibmc.
Call configure_transaction from client-side (bug 987824)
Backport focus fixes from Spartacus (bug 956959)
Merge pull request #413 from muffinresearch/backport-pin-focus-fix

Backport focus fixes from Spartacus (bug 956959)
Merge pull request #409 from muffinresearch/add-mnc-mcc-to-lobby

Call configure_transaction from client-side (bug 987824)
Allow provider to be set per request (bug 987906)
Merge pull request #412 from kumar303/helper

Allow provider to be set per request (bug 987906)
Test asset compilation (bug 991157)
Merge pull request #415 from kumar303/ci

Test asset compilation (bug 991157)
Disable payments on Android tablet (bug 976192)
method to get price from a tier (bug 990007)
Merge pull request #414 from andymckay/990007

method to get price from a tier (bug 990007)