Increase groupr.f90's maxr1 and maxr2

[cjosey]

maxr1 is the maximum number of MTs that appear. It was set to 1000 as only 1000 MT numbers can currently exist.

maxr2 is the maximum number of subsections of MF=6, 9, and 10 combined. As only MT=5 and MT=18 should need substantial space, maxr2 was increased to 2 * (maximum expected nuclides).

Tested on #350's file. While this file is not valid ENDF-6 (at least as of the current public format spec) due to having ZAP in an MF=10 MT=18 file set to something other than -1, this capability will also benefit complicated MT=5.

Test input:

moder
 20 -21/
reconr
 -21 -22/
 'intermediate step'/
 7328 1/
 0.01/
 'intermediate step'/
 0/
groupr
 -21 -22 0 -23/
 7328 1 0 3 0 1 1 1/
 'intermediate step'/
 0.0/
 1.0e0/
 5/
 1.5e8 1.6e8 1.7e8 1.8e8 1.9e8 2.0e8/
 40110300 18 ''/
 40120300 18 ''/
 0/
 0/
moder
 -23 24
stop