Document/clarify existence of iCub version 1.7 about documentation

[maggia80]

I didn't know the existence of arm 1.7.

[pattacini]

We do have it, actually.
Our codebase mirrors it: see for example https://github.com/robotology/icub-main/blob/master/src/libraries/iKin/src/iKinFwd.cpp#L1699.

[traversaro]

According to robots-configuration files, the following robots have v1.7 arms (https://github.com/robotology/robots-configuration/search?q=left_v1.7):

• iCubHertfordshire01 (https://github.com/robotology/robots-configuration/blob/f3fef4277717ae87d825a9a46d994ccd21fef3ec/iCubHertfordshire01/cartesian/left_arm_cartesian.xml#L11)
• iCubParis01 (https://github.com/robotology/robots-configuration/blob/f3fef4277717ae87d825a9a46d994ccd21fef3ec/iCubParis01/cartesianSolver.ini#L4, even if I guess the .ini file is unused and in the xml files there is no trace of 1.7)
• iCubGenova03 (https://github.com/robotology/robots-configuration/blob/f3fef4277717ae87d825a9a46d994ccd21fef3ec/iCubGenova03/cartesianSolver.ini#L4, even if I guess the .ini file is unused and in the xml files there is no trace of 1.7)

iCubHertfordshire01 is the only one that actually has 1.7 in the XML configuration files.