use script cleanup

[smanders]

some use scripts are installed even when project not part of build (wx, node)

see which projects are doing this:

cmake -DXP_DEFAULT=OFF -DXP_STEP=build /path/to/src

in staging directory: ls share/cmake/usexp-*-config.cmake

[smanders]

a nice-to-have use script enhancement: add the projects version to the front of the list of REQUIRED_VARS in the find_package_handle_standard_args() call -- also add a note to this version indicating which *pro project (externpro/internpro/etc) it came from

this will give some nice output when a project uses externpro as it reports the projects it finds (instead of the include path or whatever required variable is currently in the front of the REQUIRED_VARS list...

-- Found zlib: 1.2.8 [externpro]  
-- Found bzip2: 1.0.6 [externpro]  
-- Found boost: 1.63.0 [externpro]  
-- Found protobuf: 3.0.0-beta-1 [externpro]  
-- Found wxwidgets: 3.1 [externpro]  
-- Found geotrans: 2.4.2 [externpro]  
-- Found lua: 5.2.3 [externpro]  
-- Found openssl: 1.0.2a [externpro]  
-- Found wxx: 31 [externpro]  
-- Found libssh2: 1.5.0 [externpro]  
-- Found cares: 1.10.0 [externpro]  
-- Found curl: 7.42.1 [externpro]  
-- Found rapidxml: 1.13 [externpro]  
-- Found node: v8.11.0 [externpro]  
-- Found eigen: 3.2.7 [externpro]  
-- Found fftw: 3.3.3 [externpro]  
-- Found shapelib: 1.2.10 [externpro]  
-- Found geotiff: 1.2.4 [externpro]  
-- Found jasper: 1.900.1 [externpro]  
-- Found jpegxp: 17.08 [externpro]  
-- Found jxrlib: 15.08 [externpro]  
-- Found websocketpp: 0.7.0 [externpro]  
-- Found openh264: 1.4.0 [externpro]  
-- Found ffmpeg: 2.6.2 [externpro]  
-- Found glew: 1.13.0 [externpro]  
-- Found apr: 1.5.2 [externpro]  
-- Found expat: 2.2.5 [externpro]  
-- Found libstrophe: 0.9.1 [externpro]  
-- Found gsoap: 2.7.17 [externpro]  
-- Found rapidjson: 1.1.0 [externpro]  

[smanders]

completed with commits referenced above