Allow the addReplace action to replace existing nodes while keeping the same node id.

This allows transparent swapping of a synth (e.g. updating synthdefs with a new version) while ensuring all references to the node remain valid. Allow this on Groups for consistancy, though it's functionally identical to freeing all of the Group's children.
Fix whitespace.
Merge pull request #1130 from scztt/topic/replacenode

server: addReplace: replace existing nodes while keeping the same node id.
mergeCharFormat instead of setCharFormat, so existing format info isn't obliterated. Fixes issues #1097.
Classlib: PlotView: Don't post spec in calcSpecs
Merge pull request #1134 from scztt/topic/textview-font-color-fix

mergeCharFormat instead of setCharFormat,

so existing format info isn't obliterated. Fixes #1097.
Build: travis.yml for main qt4.
plugins: onsets, fix potential issue with multiple unsequenced increments
Build: travis, use standard cmake (nonstandard is for qt5)
Merge pull request #1135 from jamshark70/topic/removeNeedlessPosts

Classlib: PlotView: Don't post spec in calcSpecs
help: fix typo in README
update tutorial
ide: dumpOSC is updated in GUI. Issue #1136 remains unfixed though.
class library: merge now returns the class of the receiver. This fixes #1142
class library: no startup post for GeneralHID if not necessary. This fixes #1120.
class library: adjust code format
plugins: TrigControl behaves like Control. Fixes #1145
class library: adjust code format fix
class library: adjust code format
help: improve Env.step example. This fixes #1143