LTE carrier aggregation handover
This MR is to merge the phase 2 and phase 3 work from Alexander's 2017 GSoC project that was never merged. This code was previously reviewed in a Rietveld issue.
This MR enables LTE handover across carriers when carrier aggregation is used. It enables handover between primary and secondary carriers (or between secondary carriers) on a single eNB (i.e. frequency handover). It also enables handover between eNBs when the eNBs both support carrier aggregation (handover from one component carrier on one eNB to another component carrier on another eNB). The measurements code has been extended to support the multiple measurements needed on all of these carriers.
Credit due to Alexander for this original work which we should have merged many years ago, and to Sachin Nayak for rescuing it.