Added add_lesson action and form
Merge commit '46b2b7fa0d71c875f390d50726755a2ed3df3d36'
Added subject::get_subject_id, a minor fix
Merge commit '61fdca996e2fb20987be024417cec9db48ae9cac'
Added smo_user::get_learn_period_id
Added school information to the database
Extended the functionality of learn_period::get_subject_suggestions(),
Workbench model layout update
Update readme.md
Merge commit '2844e59dae4a41b9eb9bf1c101201e6cdf019ac0'

Conflicts:
	libsmo/src/learn_period.cpp