Adding Mako>=0.4.0 to global requirements

Mako>=0.4.0 is default template engine that is used by Pecan.
As well it is in requirements of Pecan:
https://github.com/stackforge/pecan/blob/master/requirements.txt#L2
So it makes sense to add it to global requirements, so we will be
able to use it in other projects without Pecan.

Change-Id: Id7b67a28c882ef00d255118f717857dd3d7021c5
Merge "Adding Mako>=0.4.0 to global requirements"