adding .gitignore file to prevent unwanted commits of potentially large files

.gitignore

+# Prerequisites
+*.d
+
+# Object files
+*.o
+*.ko
+*.obj
+*.elf
+
+# Linker output
+*.ilk
+*.map
+*.exp
+
+# Precompiled Headers
+*.gch
+*.pch
+
+# Libraries
+*.lib
+*.a
+*.la
+*.lo
+
+# Shared objects (inc. Windows DLLs)
+*.dll
+*.DLL
+*.so
+*.so.*
+*.dylib
+
+# Executables
+*.exe
+*.EXE
+*.out
+*.app
+*.i*86
+*.x86_64
+*.hex
+
+# Debug files
+*.dSYM/
+*.su
+*.idb
+*.pdb
+core
+core.*
+vgcore.*
+
+# input files
+*.dat
+*.DAT
+*.clm
+*.CLM
+*.clm2
+*.CLM2
+*.clm3
+*.CLM3
+*.nc
+*.NC
+*.nc4
+*.NC4
+*.dat
+*.DAT
+
+# output files
+*.lpj
+*.bin
+
+# processed files
+*.Rdata
+*.rdata
+*.m
+*.N
+*.csv
+*.CSV
+
+# Common desktop formats
+*.xls
+*.XLS
+*.xlsx
+*.XLSX
+*.pdf
+*.PDF
+*.doc
+*.DOC
+*.docx
+*.DOCX
+*.odt
+*.ODT
+*.ods
+*.ODS
+
+Makefile.inc
+# binaries
+bin/adddrain
+bin/addheader
+bin/asc2clm
+bin/bin2cdf
+bin/cat2bsq
+bin/catclm
+bin/cdf2clm
+bin/cdf2coord
+bin/cdf2soil
+bin/cft2clm
+bin/cfts26_lu2clm
+bin/clm2cdf
+bin/copyheader
+bin/cru2clm
+bin/cutclm
+bin/cvrtsoil
+bin/drainage
+bin/getcellindex
+bin/getcountry
+bin/grd2bsq
+bin/grid2clm
+bin/joingrid
+bin/lpj
+bin/lpj_paths.csh
+bin/lpj_paths.sh
+bin/lpjcat
+bin/lpjcheck
+bin/lpjfiles
+bin/lpjprint
+bin/lpjserver
+bin/lpjsubmit
+bin/mathclm
+bin/printclm
+bin/printdrain
+bin/printharvest
+bin/printreservoir
+bin/regridclm
+bin/regridsoil
+bin/river_sections_input_climate
+bin/river_sections_input_countrycode
+bin/river_sections_input_grid
+bin/river_sections_input_irrig
+bin/river_sections_input_landuse
+bin/river_sections_input_soil
+bin/setclm
+bin/lpjml
+bin/soil2cdf
+bin/txt2clm
+bin/txt2grid
+bin/water_use_input
+