GitLab

introduces a `none` argument for ´\enclose` to deactivate printing enclosing stuff. Documents, that this should be used with care.

fixes documentation to reflect the (merely internal) symbol commands from within co-/bi-/tangent spaces. Fixes #41.

refines \exponential and \logarithm to also work with no arguments and introduce a \expOp and an \logOp to provide more flexibility in changing the look. This closes #35.

* inverse retraction, retraction and a symbol for them
* vector transport and vector transport direction, with the additional possibility to make this dependent on a retraction
* a vector transport symbol
* creates this direction parallel transport analogue, too.

define \license for all classes and add them to the center foot of the preprint class. This closes #21