Chpt 15 exercises routine

Iteration records of the specified class in Chpt 15 exercises.

• 15.3: Quote Implementation
• 15.5: Bulk_quote Implementation
• 15.7: Limited_quote Implementation
• 15.11: virual function debug Implementation
• 15.15: Disc_quote Implementation, adapting Bulk_quote to it
• 15.16: adapting Limited_quote to Disc_quote
• 15.26: adding copy control members to Quote & Bulk_quote
• 15.27: testing how inherited constructor works in Bulk_quote