Use the freshly-built dist/*_compresssed.js and build/msg/* files
rather than using the checked-in files in the repository root.
This helps ensure that these demos are using the most recent
version of Blockly (even in the develop branch).
* Adds ln_resources script to generate Blockly symbolic links.
* Moves toolbox_standard.js into this directory. Relatedly,
updates Android and iOS copy scripts and .gitignore files.
* Corrects HTML viewport scale and disallows zoom.