Squashed 'src/univalue/' changes from f32df99..daf1285

daf1285 Merge pull request #2 from jgarzik/master
d9e62d3 Merge pull request #24 from MarcoFalke/Mf1608-cleanup
faf260f Rem unused vars and prefer prefix operator for non-primitive type
09a2693 Merge pull request #22 from laanwj/2016_04_unicode
c74a04c Merge pull request #23 from paveljanik/20160527_Wshadow
fceb4f8 Do not shadow variables

git-subtree-dir: src/univalue
git-subtree-split: daf1285af60c2c73801c0f41469c9802c849343d