Standardize demo gifs and remove from npm (#159)

Author: liorheber

README.md

@@ -12,14 +12,14 @@ Two optional themes are supported when using React Tree:
  Includes all the logic, based on @emotion/core - [README](https://github.com/kenshoo/react-tree/blob/master/packages/core/README.md)
 
   <p align="center">
-      <img src="core-tree-demo.gif?raw=true" width="288" />
+      <img src="/packages/core/demo.gif?raw=true" width="288" />
   </p>
 
  #### Material tree 
  Based on the basic tree logic, using Material-UI components - [README](https://github.com/kenshoo/react-tree/blob/master/packages/material_tree/README.md)
 
   <p align="center">
-      <img src="react-tree-demo.gif?raw=true" width="288" />
+      <img src="/packages/material_tree/demo.gif?raw=true" width="288" />
   </p>
 
 Both options support component customization. <br/>

packages/core/.npmignore

@@ -1,3 +1,4 @@
 tests
 node_modules
-cc-test-reporter
+cc-test-reporter
+demo.gif

packages/core/README.md

@@ -9,7 +9,7 @@ Examples can be found - [here](https://github.com/kenshoo/react-tree/blob/master
 
 
   <p align="center">
-      <img src="core-tree-demo.gif?raw=true" width="288" />
+      <img src="demo.gif?raw=true" width="288" />
   </p>
 
   ### Installation

packages/core/core-tree-demo.gif

@@ -1,3 +1,4 @@
 tests
 node_modules
-cc-test-reporter
+cc-test-reporter
+demo.gif

core-tree-demo.gif renamed to packages/core/demo.gif

@@ -8,11 +8,11 @@ a user to display and manage a hierarchical structure of items using <b>Material
 Examples can be found - [here](https://github.com/kenshoo/react-tree/blob/master/packages/docs/stories/core.stories.js)
 
   <p align="center">
-      <img src="react-tree-demo.gif?raw=true" width="288" />
+      <img src="demo.gif?raw=true" width="288" />
   </p>
 
   ### Installation
-  Since Material Rree is based on React Tree< logic, you need to install both <b>@kenshooui/react-tree</b> and <b>@kenshooui/material-tree</b>.
+  Since Material Tree is based on React Tree< logic, you need to install both <b>@kenshooui/react-tree</b> and <b>@kenshooui/material-tree</b>.
 
   Dependencies to <b>@material-ui/core</b> and <b>@material-ui/icons</b> are needed only if they don't exist in your project.