Add constructor call information to clang plugin

This is just a slightly modified copy of the regular function/method
call code. Unfortunately there's no place to click on the constructor
invocation to find the definition, but on clicking on the definition
you can find callers and references. I've added a creation of a
BitField object HelloWorld/main.c as an example (click on the BitField
constructor, and main in main.c can be found as a caller).
Make sure we use at least one worker when building HTML
Sort files and folders

This fixes #85.
Fix hyperlinks for members in a constructor's initialization list.

Previously in code like:
struct MyClass {
	MyClass();
	int my_member;
};
MyClass::MyClass() :
  my_member(42) {}

the last "my_member" would not be hyperlinked.
Merge pull request #83 from mook/html-at-least-one-worker

Make sure we use at least one worker when building HTML.

When there are more workers than files, we can end up with a step of 0. xrange really doesn't like that, and throws an exception. This makes sure that it gets at least 1, so that it just iterates over an empty range instead.
Minor clean up to the clang plugin makefile
- Use "llvm-config --cxxflags" and "llvm-config --ldflags"
- Add -Wno-strict-aliasing for GCC
- Don't pass -shared to the linker twice
- Use $(RM) instead of "rm -rf"
Just use a string literal for the call type.
Let us find invocations of constructors by clicking their definitions. Closes #79.
Merge Bruce's sorting of folder listings. Closes #86.
Merge 'abbeyj/member-init-links' into testing. Closes #87.
Clean up clang plugin makefile. Closes #88.
Merge testing branch into my better-testing branch, just to bring the latter up to date.

Man, these names are confusing. Really need to rename these branches.
Rename Config.template to Config.template_folder, because that's what it represents.
Move dxr-worker inside the dxr package so we can find it reliably.