README: Convert to Markdown

Makefile.am

@@ -62,7 +62,7 @@ uninstall-hook:
 EXTRA_DIST = \
 	CHANGELOG.txt \
 	LICENSE.txt \
-	README.txt \
+	README.md \
 	TODO.txt \
 	lgpl-2.1.txt \
 	$(JAVA_SRC)

README.txt → README.md

@@ -8,20 +8,24 @@ Build requirements
 Building on Linux or Mac OS X
 -----------------------------
 
+```
 ./configure
 make
 make install
+```
 
 Cross-compiling for Windows with MinGW-w64
 ------------------------------------------
 
+```
 PKG_CONFIG=pkg-config \
 	PKG_CONFIG_PATH=/path/to/cross/compiled/openslide/lib/pkgconfig \
 	./configure --host=i686-w64-mingw32 --build=$(build-aux/config.guess)
 make
 make install
+```
 
-For a 64-bit JRE, substitute --host=x86_64-w64-mingw32.
+For a 64-bit JRE, substitute `--host=x86_64-w64-mingw32`.
 
 Building on Windows
 -------------------
@@ -30,6 +34,7 @@ Ensure that the path to the openslide-java source tree does not contain
 whitespace.
 
 Install Cygwin, selecting these additional packages:
+
 - make
 - pkg-config
 - mingw64-i686-gcc-core and/or mingw64-x86_64-gcc-core
@@ -41,12 +46,14 @@ Also install a JDK and Apache Ant.
 
 Then:
 
+```
 ./configure --prefix=/path/to/install/dir \
 	--host=i686-w64-mingw32 --build=$(build-aux/config.guess) \
 	PKG_CONFIG_PATH="/path/to/openslide/lib/pkgconfig" \
 	JAVA_HOME="$(cygpath c:/Program\ Files/Java/jdk*)" \
 	ANT_HOME="/path/to/ant/directory"
 make
 make install
+```
 
-For a 64-bit JRE, substitute --host=x86_64-w64-mingw32.
+For a 64-bit JRE, substitute `--host=x86_64-w64-mingw32`.