Updates to make things work.

Some trivial things that are required to make it work on Linux.
Also updated build scripts to use Boost. You have to use
./configure --with-boost-regex=<libname, suitable for -l>


git-svn-id: svn://svn.code.sf.net/p/magicseteditor/code/trunk@1206 0fc631ac-6414-0410-93d0-97cfa31319b6

src/util/io/package_manager.hpp

@@ -63,6 +63,8 @@ class PackageDirectory {
 	void init(bool local);
 	void init(const String& dir);
 	
+	bool valid() const { return !directory.empty(); }
+	
 	/// Name of a package in this directory
 	String name(const String& name) const;
 	/// Does a package with the given name exist?