add readme, minor makefile fix

Makefile

@@ -12,7 +12,7 @@ all: dist/main.js
 
 dist/main.js: $(BC)
  @mkdir -p dist
-  $(CXX) $(LFLAGS) $(EXPORT) -o $@ $^
+  $(CXX) $(LFLAGS) $(EXPORT) -o $@ $^
 
 build/libVector_DBC.bc: $(DBC)/lib/libVector_DBC.dylib
  cp $^ $@
@@ -38,6 +38,6 @@ build/%.o: src/%.cpp $(DBC)/include/DBC.h
  $(CXX) -I./$(DBC)/include -I./lib/jsonxx $(CXXFLAGS) $(EXPORT) -o $@ $<
 
 clean:
-  if [ -a $(DBC)/build/Makefile ]; then make -C $(DBC)/build clean; fi;
+  if [ -a $(DBC)/build ]; then rm -rf $(DBC)/build; fi;
  rm -rf build
  rm -rf dist

README.md

@@ -0,0 +1,21 @@
+To get started:
+
+Download [emscripten](https://kripken.github.io/emscripten-site/index.html). I used portable SDK. You may need to change your `PATH` depending on how/what you install. If you download portable SDK, you can find SDK binaries (e.g. `emmake`) in `$SDK_ROOT/emsdk_portable/emscripten/$VERSION/`. Then run the following:
+
+```shell
+hg clone https://bitbucket.org/m2m/dbc2json.js
+cd dbc2json.js
+emmake make
+```
+
+To clean:
+
+```shell
+make clean
+```
+
+To force build (in case stuff gets out of sync):
+
+```shell
+emmake make -B
+```