initial project version
add my answer to practices from chap.1 to chap.3

 Committer: Yosuke Tanigawa <yosuke@Yosuke-MBP.local>
 On branch master
 Changes to be committed:
	new file:   README
	new file:   ex1-3
	new file:   ex2-1
	new file:   ex2-2
	new file:   ex2-3
	new file:   ex2-4
	new file:   ex2-5
	new file:   ex3-1
	new file:   ex3-2
	new file:   ex3-3
	new file:   ex4-1
	new file:   ex4-2
	new file:   ex4-3
	new file:   ex4-4
	new file:   ex4-5
Merge branch 'master' of github.com:yk-tanigawa/Perl_Lama

originのものをpullした。