Recent twister-html and twister-core updates

Some twister-core and twister-html recent updates:

- New twister-core build system using GNU Autotools (added 01-17)

- Fix long standing bug of dhtget ceasing to work (issue #32). When daemon was left running for long periods it would eventually stop processing the dhtget rpc requests. This caused the UI to become very sluggish, failing to acquire new data from the DHT network. (fixed 01-17)

- twister-html now caches the mentions results locally (html5 local storage is used). This should greatly improve user’s experience, since mentions modal now opens much faster. (added 01-18)

- New twister-html i18n branch available for translators. Thanks @toyg for maintaining it!

- Vagrant build support (thanks @kmpm)

Have fun!