Improve English man page.

The improvements fall into three categories:

  1. typos / grammar;
  2. internal consistency, eg. the format of all options is described
     using the same conventions;
  3. better semantics, eg. using .Ar instead of .Pa for arguments.
Improve Linux Makefile.

The following changes have been implemented:

  * make sure all standard (eg. $CFLAGS) variables are taken into
    account when compiling;
  * define default compilation flags in separate $MAINT_* variables
    so that user-defined variables can override them;
  * split default flags the expected way, eg. $CPPFLAGS instead of
    $CFLAGS for C preprocessor flags;
  * declare all dependencies, including the ones on header files;
  * install localized man pages in the corresponding locale-qualified
    directories, so that man(1) can pick them up automatically;
  * install .desktop file;
  * support $DESTDIR for downstream maintainers' convenience;
  * provide uninstall target;
  * get rid of symlink hackery.
Add new quirk: WS[n]
Forces a new window to appear on workspace n.

Closes #6
Add new option: urgent_collapse
Enables hiding of placeholders in the urgency hint indicator for
workspaces that do not have any urgent windows.

Closes #60
Revert "cleanup baraction.sh"

This reverts commit d78d51c80576d1afcf6bd1133f2acee91acbb7d6.