Fix Ubuntu installation with latest pandoc (citeproc), Fix tlmgr use with TinyTex

[rob-cr]

Issue

As pandoc-citeproc is depreciated (#100), the installation on linux needs the latest pandoc-version to use the successor citeproc. In addition, a standard installation of TexLive using apt and currently also via an installer is causing problems with tlmgr and some LaTex packages are missing, depending on the distribution (probably related to #84 ).

Fix

• install latest pandoc version via travis
• install TinyTex
• update install script for linux to add needed LaTex packages (using tlmgr)
• adjust PATH for tlmgr
• add Readme Quickstart for Ubuntu with those instructions (applicable for Linux in general?)

Comments

As of now, if new packages are needed in future changes, they have to be installed manually (or added in the install script), as there is no "needed packages detection" that I am aware of.

Even if TinyTex comes with advantages over full TexLive with less space (~300 MB vs. ~6500 MB) and faster installation, a full TexLive installation could be desired (or is already present on a system which eventually can cause interference with TinyTex). A way how to setup that and avoid installation problems with the full TexLive as mentioned above would be a next step, as mentioned in #100 too.

At the current state, the installation should work well with TinyTex on Ubuntu.