add 'cpp_scope_tree', use it
allow lambdas here
special-case indentation for e.g. 'class Foo :'
add infrastructure for new icons re: class, namespace, etc
don't show img when at top level
add function / lambda prototypes to scope
avoid semi-colon insertion in some special cases
ensure anonymous scopes are added
C++ modes can autoindent now
Merge pull request #170 from rstudio/feature/cpp-scope-tree

Add a C++ scope tree