WMTS createLayer method improved
OGC:CRS84 is a valid projection string too
Scale limits rounded to allow layer visibility at the end of the ranges
vars outside the loops
removed useless test on the existence of a style
Do not set serverResolutions and min/maxScale at the same time
always compute min/maxScales and set them in the layer config
updated tests
Merge pull request #1060 from georchestra/wmts/createlayer-improvements

WMTS createLayer method improved