add code in Lecture 4: State Machine.

Included are the following 7 files grouped in 2 packages:

	src/iterator/MyIterator.java
	src/iterator/WebPage.java
	src/iterator/WebPageTest.java
	src/stack/FixedSizeStack.java
	src/stack/FixedSizeStackTest.java
	src/stack/FlexibleStack.java
	src/stack/FlexibleStackTest.java

Thank you!
							Lawrence X. Amlord
							  Oct. 10th, 2014
							   Xi'an, China
add Eclipse project configuration file to code in Lecture 4.
initialize Problem Set 2: Midi Piano.

Included are the following 7 files distributed among
3 packages:

	ps2/src/midi/Instrument.java
	ps2/src/midi/Midi.java
	ps2/src/music/NoteEvent.java
	ps2/src/music/Pitch.java
	ps2/src/piano/PianoApplet.java
	ps2/src/piano/PianoMachine.java
	ps2/src/piano/PianoMachineTest.java

Thank you!
							Lawrence X. Amlord
							  Oct. 10th, 2014
							   Xi'an, China
add solution to Problem 1 in Problem Set 2.

Augmented are the following 2 files:

	src/piano/PianoMachine.java
	src/piano/PianoMachineTest.java

Thank you!
							Lawrence X. Amlord
							  Oct. 10th, 2014
							   Xi'an, China
add solution to Problem 2 in Problem Set 2.

Augmented are the following 2 files:

	src/piano/PianoMachine.java
	src/piano/PianoMachineTest.java

Thank you!
							Lawrence X. Amlord
							  Oct. 10th, 2014
							   Xi'an, China
add solution to Problem 3 in Problem Set 2.

Newly joint is the following file:

	src/music/PitchLevel.java

Besides, the following 2 files are augmented:

	src/piano/PianoMachine.java
	src/piano/PianoMachineTest.java

Thank you!
							Lawrence X. Amlord
							  Oct. 11th, 2014
							   Xi'an, China
add solution to Problem 4 in Problem Set 2.

Augmented are the following 2 files:

	piano/PianoMachine.java
	piano/PianoMachineTest.java

Thank you!
							Lawrence X. Amlord
							  Oct 12th, 2014
							   Xi'an, China
add code in Lecture 5: Regular Expression & Grammars.

Included are the following 11 files:

	.classpath
	.project
	src/markup/Gallileo.java
	src/markup/HTMLLexer.java
	src/markup/LaTeXLexer.java
	src/markup/MarkdownLexer.java
	src/markup/MarkdownLexerTest.java
	src/markup/ShuffleTest.java
	src/markup/SyntaxErrorException.java
	src/markup/Token.java
	src/markup/Type.java

Thank you!
							Lawrence X. Amlord
							  Oct 15th, 2014
							   Xi'an, China