Added a few common CAM file extensions (#2555)

Eagle.gitignore

@@ -4,6 +4,9 @@
 *.s#?
 *.b#?
 *.l#?
+*.b$?
+*.s$?
+*.l$?
 
 # Eagle project file
 # It contains a serial number and references to the file structure
@@ -31,14 +34,19 @@ eagle.epf
 *.drl
 *.gpi
 *.pls
+*.ger
+*.gpi
+*.xln
 
 *.drd
 *.drd.*
 
+*.s#*
+*.b#*
+
 *.info
 
 *.eps
 
 # file locks introduced since 7.x
 *.lck
-