quotes optimization and minor documentation changes

now we don't use quotes for simple keys and values ([A-Za-z0-9-_.]) and support single quotes (')
"fill" command has been updated to support dimension of figure [optional]
link to Python code and JSON format brief
fill command has been updated in README.md
do not read byte from stream until RX timeout's been checked
fix invalid Point's field names
Merge branch 'master' into stable