git: attributes used for svn import

This commit provides the .gitattributes used during the SVN import
process.  This avoids the need for later renormalisation if SVN
has not been consistently configured.

.gitattributes

+# Set default behaviour, this overrides core.autocrlf (as
+# no file will have an unspecified text attribute.
+* text=auto
+
+# The following force textmode when it wouldn't otherwise be
+# detected.  Probably best to keep this list short.
+*.asm text
+*.cc text
+*.cpp text
+*.c text
+*.cxx text
+*.hh text
+*.hpp text
+*.h text
+*.txt text
+
+# the following files should always have lf line endings.
+# (any editing that introduces crlf should have that stripped)
+*.awk text eol=lf
+*.sh text eol=lf
+
+# The following should always have line endings normalised to CRLF.
+# Ie, they are represented internally in git using LF and
+# converted to CRLF at checkout.
+*.sln text eol=crlf
+*.vsprops text eol=crlf
+*.vcproj text eol=crlf
+*.vcxproj text eol=crlf
+*.vcxproj.filters text eol=crlf
+*.vcp text eol=crlf
+*.vcw text eol=crlf
+*.dsw text eol=crlf
+*.dsp text eol=crlf
+*.msvc text eol=crlf
+*.bat text eol=crlf
+
+# Denote all files that are truly binary and should not be modified.
+# NB, the binary attribute below disables diff.  Only use this on
+# truly binary files, otherwise use "-text" (see above)
+*.png binary
+*.jpg binary
+*.pdf binary
+*.docx binary
+*.xlsx binary
+*.xlsm binary