False positives from search patterns in makenemo can lead to corruption of work_cfgs.txt

[dlivings]

In the current version of makenemo (last changed at [14198]), there are grep statements at lines 254, 264, and 273 and a sed statement at line 281 that search the file work_cfgs.txt for the configurations specified by the -r or -n options. Because of the way the search patterns are implemented, these searches can return multiple matches if one configuration name ends in the name of another. For example, I have a configuration DML_ORCA2_SAS_ICE that is my modification of the reference configuration ORCA2_SAS_ICE. These multiple matches can lead to corruption of work_cfgs.txt (as I have experienced). The simplest fix is to insert a caret (^) at the start of each search pattern to anchor it at the beginning of the line.