Initial org-mode integration (#1745)

- check docs/page/lsp-org.md
- fixed diagnostics reporting (there will be additional PR to fix `lsp-treemacs-errors-list`).

.gitignore

@@ -47,3 +47,9 @@ flycheck_*.el
 /*-autoloads.el
 /*-pkg.el
 /.ecukes-failing-scenarios
+
+# java stuff
+target
+.classpath
+.project
+.settings

.travis.yml

@@ -37,7 +37,7 @@ install:
 script:
   - cask build
   - cask clean-elc
-  - cask exec ert-runner -t '!no-win'
+  - cask exec ert-runner -t '!no-win' -t '!org'
   - |
     if (( ${EMACS_VERSION:0:2} < 26 )); then
         cask exec ecukes

docs/page/lsp-org.md

@@ -0,0 +1,45 @@
+# Literate programming using LSP and org-mode(alpha)
+`lsp-mode` provides **experimental** support for running the language servers
+inside of [org-mode](https://orgmode.org/) source blocks. `lsp-mode` is doing
+that by obtaining the information about the source block and then translating
+the point to the LSP positions back and forth so the server is which so the
+server actually thinks that Emacs has opened the original file. In order that to
+work the files has to be present on the disk as well because the server expects
+to find them.
+
+
+``` org
+#+BEGIN_SRC python :tangle "python.py"
+print "Hello!"
+#+END_SRC
+```
+
+## Commands
+* `lsp-org` start `lsp-mode` in source buffer.
+* `lsp-virtual-buffer-disconnect` turn off `lsp-mode`.
+
+## What works
+* `lsp-mode` core features (finding references, going to definitions, completion, lenses, highlighting, etc)
+* `company-mode`
+* `flycheck`
+* `lsp-treemacs-symbols`
+* `lsp-treemacs-errors-list`
+
+## Known limitations
+* Incremental updates are performed by sending the whole
+  buffer each time(they simulate full updates).
+* Deleting content that spans across the source block and the content of the org
+  document is not handled.
+* Opening and editing the actual file from the disk might cause undefined
+  behavour because the server expects file to be open only once.
+
+## What does not work
+* `dap-mode`
+* `lsp-ui`
+* `flymake`(?)
+
+## What's next
+- Finishing the virtual buffers `API`.
+- `lsp-ui` support
+- `dap-mode` support
+- `markdown-mode` integration