Begin code cleanup. Add promotions.jl, comment most atoms, add TODOs at required places and fix consistency issues
fix bugs in promotion
Comments and DCP checks for SOCP atoms
Added geo_mean between expression and constant
update control example. Allow indexing with :
Add vecnorm, update travis.yml to use ECOS
Update code to allow use of .+, .-, .<= etc. Fix signs in max/min. Fix bugs in stacking
fixed deprecated use of Set
simplified norm_1
fixed typo affine -> linear
Allow user to do x^2 along with square(x). Rename linear to affine.
Merge branch 'cleanup'
change linear to affine in files from master