Replace delete-backward-char with delete-char

Fixes several compilation warnings (#105)
Use string-to-number instead of the obsolete string-to-int
Enable travis-CI build job for haskell-mode

For now this only checks whether the `.el` files compile at all

Some in the future we can turn some of the warnings into errors, to
make the jobs fail...
Fix minor typo in README.md
Add Travis-CI build-status image to README.md
Replace functions used only interactively
Replace interactive-p with called-interactively-p

If support for Emacs versions prior to 23.1 is to be dropped (#156) than
interactive-p (obsolete as of 23.2) can be removed.
Merge pull request #159 from akamch/fix-warnings

Fix some of the compilation warnings
Disable showing "cl-functions" warnings in `make test`

See also #161 for the long-term plan of switching to `cl-lib`
Remove .hgignore
Reduce warnings by adding two `require`s and a `declare-function`

This addresses #105
Remove `arch-tag:` comment lines

Those were used by the "arch" version control system
Rename `test` Makefile target to `check`

...because I catch myself typing `make check`
(because that's the GNU Autotools convention).
Add `check-declare-directory` validation to `make check`
Eliminate most of remaining `make check` warnings (re #105)

This adds various `require`s and `declare-function`s

However, there's seems to be some code-smell here, as there are some
module-dep cycles which seem hard to break without reorganizing the
code. The most problematic module-dep cycle is between the following
modules:

- haskell-interactive-mode
- haskell-process
- haskell-session
- haskell-mode
Replace autoload statements in favor of ###autoload annotations

This also removes the autoloaded load-path manipulation
Tweak haskell-package.el to make it pass `make check`

haskell-package.el seems to be unfinished/dead code
Eliminate warnings (re #105) by removing legacy support

This also drops Xemacs support from inf-haskell; We can't support
Xemacs unless somebody volunteers to take over Xemacs
maintainance/support.
sort ELFILES in Makefile
Add new haskell-compat.el module for legacy support

This module shall be used for backporting/defining features which were
not available in Emacs23.x yet, like the process-live-p helper
predicate.