- merge with original master from jorgen

- minimize RAM usage of all components
- use both IRAM and DRAM in player component so we can buffer up to 1s on modules without SPI RAM
- support fragemented pcm chunks so we can use all available RAM if there isn't a big enough block available but still enough HEAP
- reinclude all components from jorgen's master branch
- add custom i2s driver to get a precise timing of initial sync
- change wrong usage of esp_timer for latency measurement of snapcast protocol
- add player component

components/esp-dsp/docs/link-roles.py

@@ -0,0 +1,46 @@
+# based on http://protips.readthedocs.io/link-roles.html
+
+from __future__ import print_function
+from __future__ import unicode_literals
+import re
+import os
+from docutils import nodes
+from local_util import run_cmd_get_output
+
+
+def get_github_rev():
+    path = run_cmd_get_output('git rev-parse --short HEAD')
+    tag = run_cmd_get_output('git describe --exact-match')
+    print('Git commit ID: ', path)
+    if len(tag):
+        print('Git tag: ', tag)
+        path = tag
+    return path
+
+
+def setup(app):
+    rev = get_github_rev()
+
+    # links to files or folders on the GitHub
+    baseurl = 'https://github.com/espressif/esp-dsp'
+    app.add_role('repo', autolink('{}/tree/{}/%s'.format(baseurl, rev)))
+    app.add_role('repo_file', autolink('{}/blob/{}/%s'.format(baseurl, rev)))
+    app.add_role('repo_raw', autolink('{}/raw/{}/%s'.format(baseurl, rev)))
+    app.add_role('example', autolink('{}/tree/{}/examples/%s'.format(baseurl, rev)))
+    app.add_role('example_file', autolink('{}/blob/{}/examples/%s'.format(baseurl, rev)))
+    app.add_role('example_raw', autolink('{}/raw/{}/examples/%s'.format(baseurl, rev)))
+
+
+def autolink(pattern):
+    def role(name, rawtext, text, lineno, inliner, options={}, content=[]):
+        m = re.search('(.*)\s*<(.*)>', text)  # noqa: W605 - regular expression
+        if m:
+            link_text = m.group(1)
+            link = m.group(2)
+        else:
+            link_text = text
+            link = text
+        url = pattern % (link,)
+        node = nodes.reference(rawtext, link_text, refuri=url, **options)
+        return [node], []
+    return role