Migrate changelog into source tree

Changelog.md

@@ -1,49 +0,0 @@
-Note: this changelog only lists feature additions, not bugfixes. For details on
-those, see the Git history.
-
-* v1.19
-    * Add `mode:` option for `create`
-    * Add `exclude:` option for `link`
-* v1.18
-    * Add `--only` and `--except` flags
-    * Add support to run with `python -m dotbot`
-    * Add `--force-color` option
-* v1.17
-    * Add `canonicalize-path:` option for `link`
-* v1.16
-    * Add `create` plugin
-* v1.15
-    * Add `quiet:` option for `shell`
-* v1.14
-    * Add `if:` option for `link`
-* v1.13
-    * Add `--no-color` flag
-* v1.12
-    * Add globbing support to `link`
-* v1.11
-    * Add force option to `clean` to remove all broken symlinks
-* v1.10
-    * Update `link` to support shorthand syntax for links
-* v1.9
-    * Add support for default options for commands
-* v1.8
-    * Update `link` to be able to create relative links
-* v1.7
-    * Add support for plugins
-* v1.6
-    * Update `link` to expand environment variables in paths
-* v1.5
-    * Update `link` to be able to automatically overwrite broken symlinks
-* v1.4
-    * Update `shell` to allow for selectively enabling/disabling stdin, stdout,
-      and stderr
-* v1.3
-    * Add support for YAML format configs
-* v1.2
-    * Update `link` to be able to force create links (deleting things that were
-      previously there)
-    * Update `link` to be able to create parent directories
-* v1.1
-    * Update `clean` to remove old broken symlinks
-* v1.0
-    * Initial commit