Arduino Builder - Spaces in path, added build cache

Bug fixes:

• Arduino builder mode: projects located at folders with spaces should compile now
• Arduino builder mode: build | clean deletes contents of the build and the cache folder
• All modes: fixed initial opening of vsCode for paths/filenames with spaces

New features:

• Arduino builder mode: activated the build cache which stores precompiled core libraries. The cache is located at {projectFolder}/.vsteensy/cache