Organize partition information fields into logical sections (#690542)

This is part of a series of changes to enable viewing all partition
information details on a minimum 800x600 display.

Part of Bug 690542 - Partition Information Dialog Warning not readable
Add partition information section titles and indent fields (#690542)

This is part of a series of changes to enable viewing all partition
information details on a minimum 800x600 display.

Part of Bug 690542 - Partition Information Dialog Warning not readable
Organize partition information into two field & value columns (#690542)

Organize the partition information field & value areas into two columns
to minimize the amount of vertical space required.

This is part of a series of changes to enable viewing all partition
information details on a minimum 800x600 display.

Part of Bug 690542 - Partition Information Dialog Warning not readable
Place partition information percentages in their own column (#690542)

On some desktop environments, such as Unity on Ubuntu 13.04, the
partition information dialog can display the used/unused/unallocated
field values overlapping with the "(##%)" percentage value.  The problem
is pronounced for values with 4 digits to the left of the decimal (for
example a 1024 MiB partition ).  To address this problem, these
percentages are placed in their own column.

Bug 690542 - Partition Information Dialog Warning not readable
Make the partition information dialog resizable (#690542)

Make the dialog resizable, add a vertical scrollbar to the information
and messages section, and set the initial height to ensure the dialog
fits entirely on an 800x600 screen.

A default height is required because some window managers, such as
fluxbox used in GParted Live, only permit resizing the height by using
the bottom corners of the dialog.  If the dialog is too large for the
screen then the user would not be able to resize it.

Note that two default initial heights are used in an effort to minimize
the amount of extra whitespace.

Bug 690542 - Partition Information Dialog Warning not readable
Remove shadow border from partition information scrollable region (#690542)

Bug 690542 - Partition Information Dialog Warning not readable
Place partition information LVM2 member names in string list (#690542)

Placing the LVM2 member names in a string list enables the member names
to be selected all at once by a user.  This was not possible with
separate label widgets for each LVM2 member name.

Bug 690542 - Partition Information Dialog Warning not readable
Center the data below the partition information graphic (#690542)

When the partition information dialog is resized, the data below the
partition graphic would remain left aligned.  Improve the aesthetics by
horizontally centering the data in the window similar to the partition
graphic.

Bug 690542 - Partition Information Dialog Warning not readable
Remove partition information vgname from status field (#690542)

With the volume group name displayed immediately below the status field,
the vgname is no longer needed in the status field.

Bug 690542 - Partition Information Dialog Warning not readable
Remove unused text_color argument from Utils::mk_label() method

None of the current GParted code uses the text_color argument for
Utils::mk_label().  Remove unused argument to simplify code.
Add optional yalign argument to Utils::mk_label() method

As part of the work on bug 652044 - uses deprecated APIs, selectable
vertical alignment was defaulted to ALIGN_CENTER for all labels.  The
relevant commits can be viewed in comment 26 of said bug report.
https://bugzilla.gnome.org/show_bug.cgi?id=652044#c26

For multi-line labels a vertical ALIGN_CENTER value is not
consistently aesthetically pleasing.  This becomes obvious when a
single-line heading label is paired with a multi-line value label.
To improve the aesthetics, a vertical alignment of ALIGN_TOP is
preferred.

Hence re-add the ability to optionally specify a vertical alignment for
labels.  If a yalign value is not specified a default vertical alignment
of ALIGN_CENTER is used.
Set top vertical alignment for multi-line field and value label pairs

A LVM volume group can contain more than one member and comprise a
multi-line entry.  As such set the "Members" field header and value
label pair to top vertical alignment.
Make LVM members selectable together in delete non-empty PV dialog

Place the LVM2 member names in a single string, separated by new lines,
so that they can be selected all together by the user.  This was not
previously possible when each member name was placed in a separate
widget.