Fiature requests for togglers

[rashevskyv]

1. Add the ability to output plain text as one of the states. Example:

-- This will overwrite you existing config
[Force update tinfoil config]
download 'https://bitbucket.org/kefir-switch/kefir/raw/master/kefir/switch/tinfoil/locations.conf' '/switch/tinfoil//locations.conf'

-- ONLY FOR USERS WITH 8GB DRAM! For uninstalling, update kefir
[8GB DRAM status]
toggle_state file_exists /config/uberhand/packages/settings/8gb.txt

toggle_on download 'https://bitbucket.org/kefir-switch/kefir/raw/master/8gb.zip' '/config/uberhand/8gb.zip'
toggle_on unzip '/config/uberhand/8gb.zip' '/8gb/'
toggle_on move '/8gb/run.te' '/startup.te'
toggle_on delete '/config/uberhand/8gb.zip'
toggle_on delete 'payload.bin'
toggle_on copy '/bootloader/payloads/TegraExplorer.bin' '/payload.bin'
toggle_on reboot

toggle_off text_source /config/uberhand/packages/settings/8gb.txt

2. Add the ability to remove a toggler (and any element in general) under a certain condition. Example:

toggle_visibility [file_exists/has_line] [file_path] <line_to_check>

If it doesn't meet the conditions, the toggler (or menu element) is not displayed. Should interact correctly with toggle_on and toggle_off