JZ/PLD: refactor dict2xform to use str.format, closes #686
Merge pull request #743 from onaio/686-refactor-dict2xform

JZ/PLD: refactor dict2xform to use str.format
DW: Owner cannot remove self from project if there is no other owner
DW: Corrected flake8 issues
DW: Checks if user is less or equal to one
ME/DW: Added remove user serializer
DW: Code refactor