Changes in adaptivity_ex2.C for -Wshadow.

Issue #24.
Changes in adaptivity_ex3.C for -Wshadow.

Issue #24.
Changes in adaptivity_ex5.C for -Wshadow.

Issue #24.
Changes in adjoints_ex1 for -Wshadow.

Issue #24.
Changes in adjoints_ex2 for -Wshadow.

Issue #24.
Changes in adjoints_ex3 for -Wshadow.

Issue #24.
Changes in adjoints_ex4 for -Wshadow.

Issue #24.
Don't include deprecated o_string_stream header.
Fixes for unused variable warnings.
Changes in adjoints_ex5 for -Wshadow.

Issue #24.
Changes in fem_system_ex1 for -Wshadow.

Issue #24.
Changes in fem_system_ex2 for -Wshadow.

Issue #24.
Changes in miscellaneous_ex3 for -Wshadow.

Issue #24.
Changes in type_vector.h for -Wshadow.

Issue #24.
Changes in miscellaneous_ex4.C for -Wshadow.

Issue #24.
Changes in miscellaneous_ex7.C for -Wshadow.

Issue #24.
Changes in reduced_basis_ex1 for -Wshadow.

Issue #24.
Changes in reduced_basis_ex3 for -Wshadow.

Issue #24.
Changes in reduced_basis_ex4 for -Wshadow.

Issue #24.
Changes in reduced_basis_ex5 for -Wshadow.

Issue #24.