Add first draft of new intro section on Live Coding

Hit 'em early on with the live coding buzz!

Author: samaaron

etc/doc/tutorial/en/01.1-Live-Coding.md

@@ -1 +1,102 @@
 # Live Coding
+
+One of the most exciting aspects of Sonic Pi is that it enables you to
+write and *modify code live* to make music, just like you might perform
+live with a guitar. This means that given some practice you can take
+Sonic Pi on stage and gig with it.
+
+## Free your mind
+
+Before we get into the real details of how Sonic Pi works in this
+tutorial, I'd like to give you an experience of what it's like to live
+code. Don't worry if you don't understand much (or any) of this. Just
+try to hold onto your seats and enjoy...
+
+## A live loop
+
+Let's get started, copy the folling code into an empty workspace above:
+
+```
+live_loop :flibble do
+  sample :bd_haus, rate: 1
+  sleep 0.5
+end
+```
+
+Now, press the `Run` button and you'll hear a nice fast bass drum
+beating away. Now, whilst it's still running, change the sleep
+value. Try something higher like `1`. Press the `Run` button again -
+notice how the drum speed has changed. Also, *remember this moment*, this
+is the first time you've live coded with Sonic Pi and it's unlikely to
+be your last...
+
+Let's add something else into the mix. Above `sample :bd_haus` add the
+line `sample :ambi_choir, rate: 0.3`. Your code should look like this:
+
+
+```
+live_loop :flibble do
+  sample :ambi_choir, rate: 0.3
+  sample :bd_haus, rate: 1
+  sleep 1
+end
+```
+
+Now, play around. Change the rates - what happens when you use high
+values, or small values? What happens if you choose a really small
+`sleep` value? Can you make it go so fast your computer can't keep up?
+
+Try commenting one of the `sample` lines out by adding a `#` to the
+beginning:
+
+```
+live_loop :flibble do
+  sample :ambi_choir, rate: 0.3
+#  sample :bd_haus, rate: 1
+  sleep 1
+end
+
+```
+
+Notice how it tells the computer to ignore it, so we don't hear it. This
+is called a comment. In Sonic Pi we can use comments to remove and add
+things into the mix.
+
+Finally, let me leave you something to play with. Take the code below,
+and copy it into a spare workspace. Now, don't try to understand it too
+much other than see that there are two loops - so two things going round
+at the same time. Now, do what you do best - experiment and play
+around. Here are some suggestions
+
+* Try changing the blue `rate:` values to hear the sample sound change
+* Try changing the `sleep` times and hear that both loops can spin round at
+different rates. 
+* Try uncommenting the two sample lines and enjoy the sound of the
+guitar played backwards.
+* Try changing any of the blue numbers
+
+
+Remember to press `Run` and you'll hear the change next time the loop
+goes round. If you end up in a pickle, don't worry - hit `Stop`, delete
+the code in the workspace and paste a fresh copy in and you're ready to
+jam again. Making mistakes is how you'll learn the quickest...
+
+
+```
+live_loop :guit do
+  with_fx :flanger, mix: 1, depth: 5 do
+    sample :guit_em9, rate: 0.5
+  end
+#  sample :guit_em9, rate: -0.5
+#  sample :guit_em9, rate: -0.25
+  sleep 8
+end
+
+live_loop :boom do
+  with_fx :reverb, room: 0.9 do
+    sample :bd_boom, amp: 10, rate: 1
+  end
+  sleep 8
+end
+```
+