Add shared library type into Travis CI build test matrix.

Site documentation update is skipped when building shared library type.
Attempt to fix shared library build using old CMake.

CMake version prior to 2.8.11 does not have LINK_LIBRARIES target property.
Better way to check old cmake version. [ci skip]
Merge remote-tracking branch 'upstream/master'
Merge branch 'master' of https://github.com/299299/Urho3D
Merge branch 'master' of https://github.com/299299/Urho3D
Fix Editor argument parsing to load startup scene correctly.
When copy-constructing a HashMap, HashSet or List, reserve initial capacity according to the size of the object being copied.
Fixed WeakPtr's operator < using wrong type argument.
Fix memory leak and potential undefined behavior in WString::Resize().
Do not allocate String's initial buffer yet when resizing to zero size. Closes #87.
Merge remote-tracking branch 'upstream/master'