update lemon version and syntax

• newer lemon is available with minor bugfixes and additional %else handling.
• change patch to handle %static directive instead of %namespace directive.

After forum discussions there is no foreseeable upstream acceptable for the %namespace patches we have introduced (the -e option might still be open to debate). Since OpenFOAM only uses the anonymous namespace to encapsulate the Lemon parser routines, just use a simpler static linkage instead. This results in a smaller, less intrusive patch, with the vague possibility that it could be upstreamed.