added new vignette

vignettes/i2dash-extension.Rmd

+---
+title: "Creating an extension package for i2dash"
+author:
+- name: Jens Preussner
+  affiliation: 
+  email: jens.preussner@mpi-bn.mpg.de
+- name: Arsenij Ustjanzew
+  affiliation: 
+  email: arsenij.ustjanzew@@gmail.com
+date: "`r BiocStyle::doc_date()`"
+package: "`r BiocStyle::pkg_ver('i2dash')`"
+output: 
+  rmarkdown::html_document:
+    toc: true
+    toc_float: true
+    fig_caption: true
+vignette: >
+  %\VignetteIndexEntry{Creating an extension package for i2dash}
+  %\VignettePackage{i2dash}
+  %\VignetteEngine{knitr::rmarkdown}
+  %\VignetteEncoding{UTF-8}
+---
+
+Vignette last complied on `r Sys.Date()`. i2dash is licenced under `r utils::packageDescription("i2dash")[["License"]]`.
+
+```{r style, echo = FALSE, results = 'asis', include = FALSE}
+BiocStyle::markdown()
+```
+
+```{r setup, include = FALSE}
+knitr::opts_chunk$set(
+    collapse = TRUE,
+    comment = "#>",
+    error = FALSE,
+    warning = FALSE,
+    message = FALSE
+)
+stopifnot(requireNamespace("htmltools"))
+htmltools::tagList(rmarkdown::html_dependency_font_awesome())
+
+library(magrittr)
+```
+
+<img src="images/i2dash_logo.png" align="center" width="150px"/>
+
+# Introduction and scope
+
+
+## Directory structure
+
+
+## Understanding of the system
+
+# Main function
+
+# Template of the component
+
+## two visualization modes
+
+# Testing the package extension
+
+# Session Info {.unnumbered}
+
+```{r sessioninfo}
+sessionInfo()
+```