Merge pull request #5 from stevenlovegrove/CRTP-update

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update comment (Switch order of so3 and translation)
Merge pull request #6 from stevenlovegrove/CRTP-update

Fix SO3 initialisation and update more non_const access to unit_quaternion
doxgen-style documentation of SO3 and SE3
update ifndef inclusion guard name
small fixes: documentation and operator*= calls fastMultliply
complete update of SO2/SE2: fully templated and documented
slightly changed complex multiplication impl.
small docu fix
docu: improve notation for exp