git housekeeping:

- added *.log files to .gitignore
- new file .gitattributes: tell git not to diff or merge binary *.bit (FPGA) files

.gitattributes

@@ -0,0 +1,4 @@
+# .gitattributes
+# prevent binary files from CRLF handling, diff and merge:
+fpga/fpga.bit -crlf -diff
+ 

.gitignore

@@ -1,6 +1,7 @@
 # .gitignore
 # don't push these files to the repository
 
+*.log
 *.o
 *.a
 *.d